EXTERNAL DESCRIPTIONS AND STAIRCASE FORMS IN IMPLICIT SYSTEMS

This paper studies the relationship between staircase forms and normal external descriptions in implicit systems. The authors show how to co mpute the proper and nonproper controllability indices of an implicit system using the reachability Hessenberg form and the corresponding no rmal external description. The normal external description of the syst em is computed using embedding techniques. Finally, the differences an d similarities between the normal external descriptions computed are s hown using the reachability and controllability Hessenberg forms of an implicit system.